"One suspect was detained and is being investigated," he added in Jaipur, the state capital. One of the explosions went off near a packed Hindu temple, leaving pools of blood outside in the street and cycles and rickshaws in a mangled heap, television pictures showed. "We will not tolerate such activities at all," said Vasundhara Raje, chief minister of the desert state.
Among the dead were a 10-year-old boy at the Hanuman (monkey god) temple, a bride in a bright red saree still wearing marriage bangles and a young man covered in blood who was left hanging over the twisted wreckage of a bicycle rickshaw, the Press Trust of India said.
Shopping bags, bloodied sandals and shoes were strewn around Johri bazaar, one of the hit markets, which security forces cleared quickly for fear of further blasts. Junior home minister Shriprakash Jaiswal told reporters, "The people responsible for these attacks have foreign connections," but he refused to point a finger directly at traditional foe Pakistan.
Police said seven blasts occurred within minutes of each other during the evening in crowded markets of old walled Jaipur, about 260 kilometres (160 miles) from New Delhi. "It's a terror attack. There was no (intelligence) report of this," police director general A.S. Gill told reporters.
Prime Minister Manmohan Singh condemned the blasts and appealed for calm, while the United States immediately condemned the wave of bombings. Historic Jaipur, which has a population of more than two million, is one of India's top tourist resorts and a favourite attraction for foreigners.
Jaipur is popularly known as the 'pink city' because of the ochre-pink hue of its hill top forts, Hindu maharajah's palaces and crenellated city walls. State borders were sealed and a high alert sounded in Rajasthan state and neighbouring areas, police said. They said there were no immediate reports of any backlash. "There is peace in the town. Nobody should worry," Arvind Jain, a senior police official, told NDTV television.
The government also issued a nation-wide security alert, particularly in New Delhi, where roadblocks were set up on major roads, and the financial capital Mumbai. US ambassador to Delhi David Mulford condemned the bombs, saying "there can be no possible justification for the murderous attack on innocent people."
The bombings took place as India marked the 10th anniversary of nuclear tests conducted on May 13 in Rajasthan, but it was unclear if there was any link.
India has been plagued by bombings across the country in recent years and routinely points the finger at foreign-based Islamic militant groups fighting New Delhi's rule in the Himalayan state of Kashmir.
In October last year, an explosion killed six people and wounded 32 in a packed cinema hall in Ludhiana in Punjab state in northern India. Police called it a "terrorist" bombing.
In August, 43 people were killed and 70 injured in the southern city of Hyderabad when attackers triggered blasts at an outdoor auditorium and a popular eatery. A series of explosions outside courts in three northern cities killed 13 last November. Analysts say extremist groups are attempting to stoke sectarian tensions to derail an India-Pakistan peace process and damage the country's booming economy.